class_docstr: Base class for DataFlow that proxies another.
  Every method is proxied to ``self.ds`` unless overriden by a subclass.
docstr: Args:
      ds (DataFlow): DataFlow to proxy.
docstr_tok: ["Args",":","ds","(","DataFlow",")",":","DataFlow","to","proxy","."]
code: def __init__(self, ds):
      """
      Args:
          ds (DataFlow): DataFlow to proxy.
      """
      self.ds = ds
  
imports: import threading
  from abc import ABCMeta, abstractmethod
  import six
  from ..utils.utils import get_rng
label_desc: Use image node_id 1 to create a new ProxyDataFlow object from inherited base classes: DataFlow with example: obj = ProxyDataFlow(ds)